The present invention relates to an apparatus for feeding successively sheet like members such as sheet like documents, sheet like photosensitive papers, sheet like image receiving papers, etc. which are manually supplied to the sheet feed apparatus one by one by a user.
For instance, in a duplicating apparatus there have been developed a sheet feed apparatus comprising rollers which feed a sheet like document or a recording paper which is manually brought by a user at a position which is an upstream side of the rollers. A further known sheet feed apparatus comprises a belt conveyer device installed in a document cover, said belt conveyer device feeds the sheet like document to a given exposing position at which the stationary document is exposed by a moving optical system or a one-shot exposing optical system. In a Japanese Patent Application Publication No. 2,579/75 there is also described a sheet feed apparatus which comprises a first pair of rollers made of soft and resilient material and arranged at an entrance of the apparatus and a second pair of rollers arranged at a downstream relative to the first pair of rollers. The first pair of rollers is made rotatable in a forward feed direction until a front edge of the sheet is grasped by the second pair of rollers and after that the first pair of rollers is driven in an opposite direction so as to stretch folded or shrunk sheets. Further in a Japanese Patent Application Laid-Open Publication No. 8,247/73 there is disclosed a sheet feed apparatus comprising at least two pairs of feed rollers arranged integrally with a document table. In this apparatus the document is exposed while it is fed between the pairs of feed rollers.
In the above mentioned known sheet feed apparatuses since the member for feeding the sheets is made always operative or is made operative immediately after a detection of the supply of the sheet, the sheet might be fed while it is not in a correct position and thus there is a fear that the sheets might be folded or shrunk. Therefore the user must supply the sheets very carefully. Such a document supply operation is quite combersome and the user is subjected to a mental stress.
In order to avoid the above mentioned drawbacks of the known sheet feed apparatuses there has been devised another known apparatus which comprises a first mechanism for feeding a manually supplied document into a given position and a second mechanism for further feeding the document from the given position into a duplicating position after ascertaining the document being in a correct position at the given position. The first feeding mechanism comprises rollers which feed the document to a given corner after detecting photoelectrically the document and the second mechanism is made operative upon a detection signal which is produced when the edge of the document is brought into the given corner. This sheet feed mechanism can feed the manually supplied sheet like document with correct position. However the apparatus is very complicated and is large in size and thus is quite expensive. Further if the document is thin and transparent or translucent, the operation might be unstable and an erroneous operation might occur.